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Biomedical subjects

A K Tandon

Publications and source records attributed to A K Tandon.

At least 19 recordsLinked to original sources

Prognosis and treatment decisions in patients with breast cancer without axillary node involvement.

BACKGROUND: Every month, treatment decisions must be made for more than 6000 patients with breast cancer without axillary node involvement in the United States. Approximately 70% of these patients will survive more than 10 years after surgery and/or radiation treatment without additional systemic adjuvant therapy. If we had good methods to identify patients who are destined to have a recurrence of their disease, only those patients should receive adjuvant therapy. METHODS: The authors reviewed the literature supporting the use of currently available prognostic factors for patients with node-negative breast cancer, and formulated a framework on which prognostic factor information can be based to help make these treatment decisions. RESULTS: The steps involved in making treatment decisions are: use prognostic factors to determine the recurrence probability; calculate the expected treatment benefit; and weigh the expected benefits against the potential risks. CONCLUSIONS: Prognostic factors can be used to help make treatment decisions for patients with breast cancer without axillary node involvement. However, the final treatment decision must take into account all aspects of the patient and her disease, and the physician must help the patient evaluate her prognostic factors, arrive at an understanding of her particular risk of recurrence, and weigh the potential benefits and risks of adjuvant therapy.

Axilla

Inhibition of breast cancer cell growth in vitro by a tyrosine kinase inhibitor.

Human breast cancer cell proliferation is regulated by growth factors that bind to receptors with intrinsic tyrosine kinase (TK) activity, including the epidermal growth factor (EGF) receptor. To determine whether inhibition of receptor TK activity inhibits tumor growth, we studied the effects of a tyrosine kinase inhibitor, RG-13022, on cultured human breast cancer cells. RG-13022 represents a class of compounds which have been shown to inhibit preferentially the TK activity of the EGF receptor in a cell-free system and also to inhibit EGF-stimulated growth of cultured cells. RG-13022 significantly inhibited EGF-stimulated autophosphorylation of its receptor in two breast cancer cell lines that have abundant, although not amplified, EGF receptor content (MDA-231 and T47D). RG-13022 also inhibited EGF-stimulated DNA synthesis and proliferation of T47D and MCF-7 breast cancer cells in a reversible and dose-dependent manner. Inhibition was observed at 0.1 microM, and it was maximal at 10 microM. The effect was rapid (within 3 h), persisted for 18 h, and was partially reversed by 24 h at 1 microM. At 5 microM, inhibition persisted for more than 50 h. Inhibitory effects were also observed in a panel of estrogen receptor-positive and estrogen receptor-negative breast cancer cell lines. RG-13022 inhibited not only EGF-induced growth but also growth stimulated by insulin, insulin-like growth factor I, insulin-like growth factor II, or transforming growth factor alpha. RG-13022 also totally blocked estrogen-stimulated phosphorylation of the EGF receptor, as well as estrogen-induced cell proliferation, suggesting that functioning TK pathways are required for estrogen action. The TK inhibitor RG-13022 is a potent inhibitor of hormonally regulated growth of human breast cancer. Tyrosine kinase inhibitors have the potential of providing a new strategy for the "endocrine therapy" of breast cancer.

Breast Neoplasms

Overexpression of HER-2/neu and its relationship with other prognostic factors change during the progression of in situ to invasive breast cancer.

Using permanent-section immunohistochemistry, we investigated the role of HER-2/neu in the development and progression of human breast cancer by measuring its overexpression in a series of hyperplastic (n = 30), dysplastic (n = 15), and malignant neoplastic (n = 708) lesions of ductal epithelium and by evaluating the relationships between overexpression and clinicopathologic features known to have prognostic significance in these lesions. The neoplasms included pure ductal carcinoma in situ (DCIS; n = 59) and infiltrating ductal carcinoma (IDC; n = 649). The latter were all node negative and stratified into IDC combined (n = 237) or not combined (n = 412) with a "significant amount" of DCIS (defined as DCIS greater than or equal to 10% of total tumor cellularity). Overexpression of HER-2/neu was not observed in any of the hyperplastic or dysplastic lesions. In contrast, it was present in 56% of pure DCIS and in 77% of the comedo subtype of this group. Only 15% of IDC overexpressed HER-2/neu. However, the rate of overexpression was significantly higher in the subset of IDC combined with DCIS compared with the subset of IDC not combined with DCIS (22% v 11%, respectively; P less than .0001). These results are consistent with the hypothesis that HER-2/neu plays a more important role in initiation than in progression of ductal carcinomas. They also suggest that overexpression decreases within individual tumors as they evolve from in situ to increasingly invasive lesions or, alternatively, that many invasive carcinomas arise de novo (ie, without progressing through a significant in situ stage) by mechanisms not involving HER-2/neu. In addition, overexpression of HER-2/neu was associated with several poor prognostic features (younger patient age, premenopause, negative estrogen receptor status, negative progesterone receptor status, and high nuclear grade) in the subset of IDC combined with DCIS. With one exception (negative estrogen receptor status) these associations were lost in IDC not combined with DCIS, also suggesting that the role of HER-2/neu changes during the progression of human breast cancer.

Biomarkers, Tumor

A technique for retrieving antigens in formalin-fixed, routinely acid-decalcified, celloidin-embedded human temporal bone sections for immunohistochemistry.

The application of immunohistochemistry to routinely decalcified, celloidin-embedded human temporal bone sections has been hampered because of antigen loss during processing of the specimens. To our knowledge, there has been no published report to date describing immunohistochemical staining of such tissues suitable for examination by light microscopy. Here we report a novel antigen retrieval technique which can be successfully used to stain a variety of antigens in routinely formalin-fixed, trichloroacetic acid-decalcified, celloidin-embedded human temporal bone sections. The new procedure reported here for decalcified human temporal bone tissues simply requires immersing slides for 30 min at room temperature in an antigen retrieval solution. A total of 60 decalcified, celloidin-embedded human temporal bone tissues were tested with monoclonal antibodies (MAb) to 15 different antigens. Of these, 12 MAb showed definite positive staining, while three were negative. This technique may prove very useful in studying the expression of various antigens by immunohistochemistry in formalin-fixed, acid-decalcified, celloidin-embedded tissues.

Antibodies, Monoclonal

HER-2/neu in node-negative breast cancer: prognostic significance of overexpression influenced by the presence of in situ carcinoma.

PURPOSE: Amplification and/or overexpression of the HER-2/neu oncogene have been shown to correlate with poor clinical outcome in patients with axillary node-positive breast cancer. In contrast, the prognostic significance of HER-2/neu in node-negative disease is controversial. This study was undertaken to evaluate further the relationship between HER-2/neu and clinical outcome in node-negative disease. PATIENTS AND METHODS: Overexpression of HER-2/neu was evaluated by permanent-section immunohistochemistry in tumors from 613 patients with long-term clinical follow-up enrolled in the Intergroup Study 0011. Patients were stratified into low-risk (n = 307) and high-risk (n = 306) groups on the basis of tumor size and estrogen-receptor (ER) status. Low-risk patients were defined as having small (less than 3 cm), ER-positive tumors and were observed without additional treatment after initial surgery. High-risk patients had either ER-negative or large (greater than or equal to 3 cm), ER-positive tumors and were randomized to be observed (n = 146) or to receive adjuvant chemotherapy (n = 160) after surgery. RESULTS: The rate of HER-2/neu overexpression was 14.3% in all tumors combined and was higher in invasive carcinomas with (21.5%) than without (11.2%) a significant noninvasive or in situ histologic component (P less than .0001). There was no relationship between overexpression and clinical outcome in the natural history setting of combined low-risk and high-risk patients not receiving adjuvant therapy (n = 453). Based on the reasoning that the influence of HER-2/neu may have been obscured by high-risk features and/or the presence of noninvasive carcinoma, we also analyzed the subset of patients with low-risk lesions not containing a significant in situ component (n = 179). Patients of this group with HER-2/neu-positive tumors showed only 40% disease-free survival (DFS) at 5 years, compared with over 80% in patients with HER-2/neu-negative tumors (P less than .0001). A similar inverse correlation was observed between overexpression and overall survival in the same group of patients (P = .0001). In a separate analysis involving patients receiving adjuvant chemotherapy, those with HER-2/neu-negative tumors showed significantly improved DFS in response to therapy compared with patients with HER-2/neu-positive tumors. CONCLUSION: Overexpression of HER-2/neu is associated with poor clinical outcome in a subset of node-negative patients with small, ER-positive, predominantly invasive tumors and may play a role in resistance to adjuvant chemotherapy.

Breast Neoplasms

S-100 protein in human inner ear: use of a novel immunohistochemical technique on routinely processed, celloidin-embedded human temporal bone sections.

The authors recently developed a new antigen retrieval technique which allows immunohistochemical detection of proteins in routinely processed, celloidin-embedded human temporal bone sections. This technique was used in the present study, which reports the occurrence of S-100 protein in the human inner ear. Fifteen celloidin-embedded human temporal bone sections, obtained from the Eastern Temporal Bone Bank at the Massachusetts Eye and Ear Infirmary, were tested with the monoclonal antibody to S-100. This protein was found in the spiral ligament, in Reissner's membrane, in the spiral limbus, and in the basement membrane of the cochlea. S-100-positive, thin fibers could be seen as supporting elements in the acoustic nerve and the facial nerve. This protein was localized along the surface of vestibular wall. The new technique provides an immunohistochemical approach to studying routinely processed human temporal bone sections and may prove useful in the field of immuno-otopathology.

Collodion

Treatment decisions in axillary node-negative breast cancer patients.

Treatment decisions must be made on 9000 axillary node-negative breast cancer patients each month in the United States. Which of these patients will benefit from adjuvant therapy is a major question. Valid methods are needed to distinguish those patients who are "cured" from those who will suffer a cancer recurrence. A complex network of prognostic variables enters into the treatment decision, together with a risk-versus-benefit assessment. We are using a neural-network-based form of artificial intelligence that, once "trained" with data representing an event and its outcome, can identify subsets of patients with low recurrence risks. Larger data sets are being evaluated with the hope of introducing the neural-network technique to routine clinical practice.

Breast Neoplasms

Variant human breast tumor estrogen receptor with constitutive transcriptional activity.

Since progesterone receptor (PgR) is normally induced by estrogen, breast cancer lacking estrogen receptor (ER) would also be expected to lack PgR. However, a small percentage of breast cancers are ER- yet PgR+. These tumors might possess an ER which is defective in estrogen binding but is still functional in stimulating estrogen-responsive genes such as PgR. We have now detected such a variant, lacking exon 5 of the hormone-binding domain, using complementary DNA amplified by the polymerase chain reaction. This variant was the predominate ER RNA expressed in three ER-/PgR+ tumors. Furthermore, the variant ER constitutively activates transcription of a normally estrogen-dependent gene construct in yeast cells. The variant ER could explain the expression of PgR in certain tumors and have therapeutic implications.

Base Sequence

HER-2/neu amplification predicts poor survival in node-positive breast cancer.

HER-2/neu protooncogene amplification and protein expression were analyzed with slot blot and Western blot techniques, respectively, in more than 300 invasive primary breast tumors of all stages. Amplification (2- greater than 30 copies) was found in 17% of these tumors and high expression was seen in 19%. There was a striking coincidence between gene amplification and high expression. Tumors associated with many involved axillary lymph nodes or with Stage IV disease were more often HER-2/neu amplified or overexpressed. Furthermore, gene alteration was strongly correlated with the absence of steroid receptors and with larger tumor size. High expression without gene amplification was seen in a minor subset of tumors of less aggressive character. Neither amplification nor overexpression was correlated with disease outcome for patients with negative axillary lymph nodes. For node-positive patients, however, HER-2/neu amplification was a significant predictor of early relapse and death (median follow-up = 45 months), and a similar trend, although not significant, existed for high gene expression. Multivariate analyses indicated that HER-2/neu alterations were not independent predictors of patient outcome.

Amino Acid Sequence

Association of the 323/A3 surface glycoprotein with tumor characteristics and behavior in human breast cancer.

We have earlier described a monoclonal antibody (323/A3) against a Mr 43,000 surface glycoprotein of MCF-7 human breast cancer cells which shows considerable specificity for primary and metastatic breast tumors (Cancer Res., 46: 1306-1317, 1986). Here we report the occurrence of the 323/A3 antigen in a large cohort of primary breast tumors (m = 384) and its interrelationship with several clinically important variables. Frozen, stored tumor tissues were examined by a Western blot procedure, and the level of 323/A3 protein in individual tumors was calculated in arbitrary units based on the integrated Mr 43,000 signal in tumors compared with an MCF-7 internal standard. Thirty-six % (139 of 384) of tumors were found to be positive for 323/A3. Higher frequencies of 323/A3 protein were found in tumors larger than 2 cm (P = 0.03), tumors with infiltrated lymph nodes (P = 0.01), and tumors without estrogen receptor (P = 0.006). No significant relationship was found with patient age, menopausal status, or progesterone receptor status. Of the newer clinical determinants proliferative rate (% S phase), DNA ploidy, and the lysosomal protease cathepsin D, but not the HER-2/neu oncogene protein, were significantly correlated with 323/A3. The presence of 323/A3 protein was also related to increased recurrence (P = 0.003) and mortality (P = 0.036) after primary treatment. As an exposed surface antigen, this glycoprotein might be a useful target in radioimaging and immunotherapy of some human breast tumors, especially those having large size, infiltrated lymph nodes, deficient estrogen receptor, high proliferative rate, abnormal DNA content, and high levels of cathepsin D, all of which are ominous indicators of tumor behavior.

Adult

Cathepsin D and prognosis in breast cancer.

We investigated the possibility that cathepsin D, an estrogen-induced lysosomal protease, might have value as a prognostic factor in breast cancer by studying frozen tissue specimens from 397 patients. We measured the 34-kd mature form of the enzyme by Western blot assay and densitometry. Among 199 patients with node-negative disease, but not among 198 with node-positive disease, high levels of cathepsin D proved to be a significant predictor of reduced disease-free survival (median follow-up, 64 months), either as a continuous variable (log cathepsin D; P = 0.018) or as a dichotomous variable with an optimized cutoff point (P = 0.0001). Results were similar for overall survival (P = 0.009 and 0.0001, respectively). Relating the level of cathepsin D to other prognostic factors in the patients with node-negative disease, we found an association with aneuploidy but none with estrogen or progesterone receptors, tumor size, or the age of the patient. In multivariate analyses, a high level of cathepsin D was the most important independent factor in predicting shorter disease-free and overall survival in patients with node-negative disease. As compared with the risk in women with low levels of cathepsin D, the relative risk of tumor recurrence was 2.6 (95 percent confidence interval, 1.6 to 4.4) and the relative risk of death was 3.9 (95 percent confidence interval, 2.1 to 7.3) among those with high levels of cathepsin D. For disease-free survival, cathepsin D status was predictive of outcome primarily among those with aneuploid tumors; the actuarial five-year recurrence rates of aneuploid tumors were 60 percent among women with high levels of cathepsin D and 29 percent among those with low levels, as compared with 22 percent for all diploid tumors. We conclude that cathepsin D may be an independent predictor of early recurrence and death in node-negative breast cancer.

Biomarkers, Tumor

Isolation and characterization of an adriamycin-resistant breast tumor cell line.

An adriamycin-resistant human breast tumor cell line MDA-A1R was generated by step-wise selection in increasing concentrations of drug from the parent cell line MDA-MB-231. MDA-A1R cells grow as loosely attached cell aggregates with a doubling time of 28-32 h; the MDA-MB-231 parent cell line grows as a standard monolayer culture with a 20-h doubling time. The MDA-A1R cell line is highly resistant to adriamycin compared to the parent cell line, and is cross-resistant to velban and colchicine suggestive of a multidrug resistance (MDR) phenotype. MDA-A1R cells exhibit reduced net adriamycin content as compared to the parent cell line. The MDR-associated P-glycoprotein gene is amplified approximately 10- to 30-fold in MDA-A1R cells. P-glycoprotein sequences are overexpressed in the resistant cells and are stable for up to 13 wk after drug removal. Moreover, MDA-A1R cells show the presence of very high levels of P-glycoprotein. MDA-A1R is thus an in vitro model system to study the mechanism of MDR in human breast cancer.

ATP Binding Cassette Transporter, Subfamily B, Mem

HER-2/neu oncogene protein and prognosis in breast cancer.

Amplification of the HER-2/neu oncogene was recently reported to predict poor clinical outcome in node-positive breast cancer patients. Since expression of the oncogene as its protein product might be even more closely related than gene amplification to disease progression, we have now examined levels of the HER-2/neu oncogene protein for its prognostic potential in both node-positive and node-negative breast cancer. Using Western blot analysis, levels of this protein were determined in 728 primary human breast tumor specimens. We examined relationships between this protein and other established markers of prognosis, as well as clinical outcome. In node-negative patients (n = 378), the HER-2/neu protein failed to predict disease outcome. However, in node-positive patients (n = 350), those patients with higher HER-2/neu protein had statistically shorter disease-free (P = .0014) and overall survival (P less than .0001) than patients with lower levels of the protein. Higher HER-2/neu protein was found in tumors without estrogen receptor (ER) (P = .02) or progesterone receptor (PgR) (P = .0003), and in patients with more than three positive lymph nodes (P = .04). A significant correlation between levels of the HER-2/neu gene protein and amplification of the gene itself was also found (n = 48, P less than .001). Multivariate analyses in these patients showed that the HER-2/neu protein is a significant independent predictor of both the disease-free and the overall survival in node-positive breast cancer, even when other prognostic factors are considered.

Antibody Specificity

Electrophoretic analysis of 248 clinical breast cancer specimens for P-glycoprotein overexpression or gene amplification.

Multiple drug resistance (MDR), consisting of acquired cross resistance to anthracyclines, vinca alkyloids, and other antineoplastic antibiotics, has been described in a variety of cell lines. This MDR phenotype is associated with overexpression and sometimes amplification of a gene coding for a 170 kDa glycoprotein, termed P-glycoprotein. To understand the role of this mechanism in clinical breast cancer, 248 breast cancer specimens representing both untreated primary and refractory relapsing disease were probed for evidence of P-glycoprotein gene amplification or overexpression using Southern, Northern, or Western blot techniques. In no case was an increase in P-glycoprotein gene copy number or expression detected. Though these findings do not necessarily rule out a role for P-glycoprotein in mediating drug resistance in breast cancer, electrophoretic analysis of clinical specimens is unlikely to provide useful predictive information. More sensitive assays must be developed to overcome the difficulties inherent in analyzing heterogenous tissue samples.

ATP Binding Cassette Transporter, Subfamily B, Mem

Dermatitis artefacta.

Dermatitis artefacta is an uncommonly encountered condition. This paper presents a case report of two such rare patients. The symptomatology and history of fourteen and sixteen year old males with dermatitis artefacta are described. Possible psychophysiological aetiology of the cases is discussed.

Adolescent